Association between a Post-Resuscitation Care Bundle and the Odds of Field Rearrest after Successful Resuscitation from Out-of-Hospital Cardiac Arrest: A Pre/Post Study.

OBJECTIVES: Rearrest after successful resuscitation from out-of-hospital cardiac arrest (OHCA) is common and is associated with worse patient outcomes. However, little is known about the effect of interventions designed to prevent rearrest. We assessed the association between a prehospital care protocol for immediate management after return of spontaneous circulation (ROSC) and rates of field rearrest and survival to discharge in patients with prehospital ROSC. METHODS: This was a retrospective study of adult patients with OHCA and field ROSC within a large EMS system before (April 2017-August 2018) and after (April 2019-February 2020) implementation of a structured prehospital post-ROSC care protocol. The protocol was introduced in September 2018 and provided on-scene stabilization direction including guidance on ventilation and blood pressure support. Field data and hospital outcomes were used to compare the frequency of field rearrest, hospital survival, and survival with good neurologic outcome before and after protocol implementation. Logistic regression was used to assess the association between the post-implementation period and these outcomes, and odds ratios were reported. The association between individual interventions on these outcomes was also explored. RESULTS: There were 2,706 patients with ROSC after OHCA in the pre-implementation period and 1,780 patients in the post-implementation period. The rate of prehospital rearrest was 43% pre-implementation vs 45% post-implementation (RD 2%, 95% CI -1, 4%). In the adjusted analysis, introduction of the protocol was not associated with decreased odds of rearrest (OR 0.87, 95% CI 0.73, 1.04), survival to hospital discharge (OR 1.01, 95% CI 0.81, 1.24), or survival with good neurologic outcome (OR 0.81, 95% CI 0.61, 1.06). Post-implementation, post-ROSC administration of saline and push-dose epinephrine increased from 11% to 25% (RD 14%, 95% CI 11, 17%) and from 3% to 12% (RD 9% 95% CI 7, 11%), respectively. In an exploratory analysis, push-dose epinephrine was associated with a decreased odds of rearrest (OR 0.68, 95% CI 0.50, 0.94). CONCLUSIONS: Introduction of a post-ROSC care protocol for patients with prehospital ROSC after OHCA was not associated with reduced odds of field rearrest. When elements of the care bundle were considered individually, push-dose epinephrine was associated with decreased odds of rearrest.

Older Adult Frequent 9-1-1 Callers for Emergency Medical Services in a Large Metropolitan City: Individual- and System-Level Considerations.

BACKGROUND: High utilizers of 9-1-1 place a substantial burden on emergency medical services (EMS). Results of a retrospective review of records data of the City of Los Angeles Fire Department (LAFD) showed a significant increase in older adult high utilizers of 9-1-1. OBJECTIVE: The objective of this study was to explore individual- and system-level factors implicated in EMS use among older adults, and to provide system recommendations to mitigate overuse. METHODS: A phenomenological study was conducted, drawing from LAFD EMS records between 2012 and 2016 to identify and contact high-utilizing patients older than 50 years, their family, agency representatives, and LAFD personnel. Interviews were recorded, transcribed, and coded and a thematic analysis was completed. RESULTS: We conducted in-depth interviews with 27 participants, including patients (n = 8), their families (n = 6), social service agency representatives (n = 3), and LAFD personnel (n = 10). The following cross-cutting themes emerged: nature of 9-1-1 calls, barriers to access, and changing the system. In addition, LAFD and social service agency representatives identified the role of EMS responders and social agency representatives. Patients and their families agreed that previous encounters and interactions with emergency care responders were relevant factors. CONCLUSIONS: This study described reasons for 9-1-1 calls related to medical and social service needs, including mental health care. Our analysis offers insight from different stakeholders' perspectives on access to medical care and types of barriers that interfere with medical care. All groups shared recommendations to advance access to medical and mental health care.

Prehospital Predictors of Atypical STEMI Symptoms.

Introduction: Rapid prehospital identification of patients with ST-elevation myocardial infarction (STEMI) is a critical step to reduce time to treatment. Broad screening with field 12-lead ECGs can lead to a high rate of false positive STEMI activations due to low prevalence. One strategy to reduce false positive STEMI interpretations is to limit acquisition of 12-lead ECGs to patients who have symptoms strongly suggestive of STEMI, but this may delay care in patients who present atypically and lead to disparities in populations with more atypical presentations. We sought to assess patient factors associated with atypical STEMI presentation.Methods: We retrospectively analyzed consecutive adult patients for whom Los Angeles Fire Department paramedics obtained a field 12-lead ECG from July 2011 through June 2012. The regional STEMI receiving center registry was used to identify patients with STEMI. Patients were designated as having typical symptoms if paramedics documented provider impressions of chest pain/discomfort, cardiac arrest, or cardiac symptoms, otherwise they were designated as having atypical symptoms. We utilized logistic regression to determine patient factors (age, sex, race) associated with atypical STEMI presentation.Results: Of the 586 patients who had STEMI, 70% were male, 43% White, 16% Black, 20% Hispanic, 5% Asian and 16% were other or unspecified race. Twenty percent of STEMI patients (n = 117) had atypical symptoms. Women who had STEMI were older than men (74 years [IQR 62-83] vs. 60 years [IQR 53-70], p < 0.001). Univariate predictors of atypical symptoms were older age and female sex (p < 0.0001), while in multivariable analysis older age [odd ratio (OR) 1.05 per year, [95%CI 1.04-1.07, p < 0.0001] and black race (OR vs White 2.18, [95%CI 1.20-3.97], p = 0.011) were associated with atypical presentation.Conclusion: Limiting prehospital acquisition of 12-lead ECGs to patients with typical STEMI symptoms would result in one in five patients with STEMI having delayed recognition, disproportionally impacting patients of older age, women, and Black patients. Age, not sex, may be a better predictor of atypical STEMI presentation.

Emergency Medical Services Utilization by Homeless Patients.

BACKGROUND: Homelessness is a rapidly growing issue throughout the United States and has important public health implications. Los Angeles, like other large urban cities, has seen a recent increase in homelessness. However, little is known about emergency medical service (EMS) utilization by those experiencing homelessness. Objective: Describe the utilization of emergency medical services by homeless patients. Methods: This is a 12-month retrospective review of electronic health records of all 911-incidents attended by the Los Angeles Fire Department (LAFD) from January to December 2018. The City of Los Angeles is 480 square miles and has a population of 3,949,776 with a homeless population of 31,285 (0.8% of city population). The primary outcome is the frequency of EMS 911-calls for homeless patients. Secondary outcomes include call characteristics. Results: There were 355,411 911-incidents during the study period. Homeless patients were involved in 36,122 (10.2%) incidents. Incidents for the homeless population occurred at a rate of 1155 per 1000 homeless residents or 14 times the rate of housed residents. Of the 217,972 calls resulting in transport to the emergency department, 28,917 (13.3%) were for homeless patients. This translates into a rate of 924 per 1000 homeless patients, which is 19 times higher than housed patients. Homeless patients were younger (mean 46.1 v 52.6 years) and more likely to be male (71% v 49.1%). Acuity was lower in the homeless group, 31.4% v 42.5% received advanced life support. Conclusion: In the City of Los Angeles, people experiencing homelessness demonstrated disproportionately high use of EMS services and ambulance transports, were more frequently younger, male, and had lower acuity conditions when compared with housed patients.

Impact of a New 9-1-1 Dispatch System on Call-Processing Times for Time-Critical Emergencies in the City of Los Angeles.

Objective: To determine the impact of a new emergency medical services (EMS) 9-1-1 dispatch system on call-processing times for field-confirmed time-critical emergencies. Methods: An interrupted time series study compared 9-1-1 calls for field-confirmed emergencies processed by Los Angeles Fire Department (LAFD)-telecommunicators using either the Medical Priority Dispatch System® (January 1 - September 30, 2014) or the new Los Angeles Tiered Dispatch System (January 1 - September 30, 2015). Prior to the study, authors identified seven categories of time-critical emergencies. Cases meeting inclusion criteria were systematically identified using LAFD electronic health records, and the elapsed time from call receipt to key events were obtained. The primary outcome was call-processing time (CPT), defined as time from 9-1-1 call receipt to when resources were dispatched. Results: During the study period, 12,439 incidents met inclusion criteria: 6,208 using MPDS and 6,231 using LA-TDS. Among all unique time-critical incidents, the mean CPT was 16 seconds faster using LA-TDS (M = 68.5) compared to MPDS (M = 84.4; p < 0.001). CPT was significantly (p < 0.01) lower using LA-TDS for: cardiac arrests with attempted resuscitation, patients requiring ventilation support, seizures requiring prehospital benzodiazepines, gunshot wounds with hypotension, automobile vs. pedestrian accidents, and long falls. There was no difference in CPT for drownings requiring resuscitation (p = 0.60). The elapsed time to arrival of first responders on scene improved from 370.1 seconds using MPDS to 354.8 seconds using LA-TDS (p < 0.001). Conclusion: The new Los Angeles Tiered Dispatch System significantly improved 9-1-1 call-processing times and total response times for nearly all identified time-critical emergencies under study.

Effect of New 9-1-1 System on Efficiency of Initial Resource Assignment.

Objective: To determine the impact of a new dispatch system on the efficiency of first resource assignment for critical EMS patients. Methods: In December 2014, the Los Angeles Fire Department (LAFD) implemented a new, internally-developed dispatch system. An interrupted time series study compared 9-1-1 incidents processed by LAFD-telecommunicators using either the Medical Priority Dispatch System® (MPDS, January 1 - September 30, 2014), or Los Angeles Tiered Dispatch System (LA-TDS, January 1 - September 30, 2015). All incidents were assigned a Dispatch Level of Service (DLOS), based on whether a basic life support (BLS) or advanced life support (ALS) resource was dispatched, and a Field-Recommended Level of Service (RLOS), a metric based on medical necessity, required scope of practice, number and intensity of interventions, and patient severity. DLOS options included BLS or ALS, whereas RLOS options included BLS, ALS1 and ALS2, with ALS2 cases having the greatest medical need. The primary outcome was critical under-triage rate, and secondary outcomes included rates of over-triage, total resource utilization and test characteristics of each dispatch system. Results: 563,188 incidents met inclusion criteria, including 271,604 using MPDS and 291,584 using LA-TDS. During the MPDS period, 96,561 (35.6%) incidents were initially dispatched with BLS resources (including 194 (0.071% ultimately found in the field to be high-acuity RLOS ALS2), and 175,043 were dispatched with ALS resources. During the LA-TDS period, 127,827 (43.8%) were dispatched as BLS (including 154 RLOS ALS2) and 163,798 were dispatched as ALS. For the primary outcome, the critical under-triage rate was 0.20% using MPDS and 0.12% using LA-TDS (Z 4.7, p < 0.0001, RR 0.61 CI 95% 0.50-0.76), and this improvement was primarily driven by improved triage of cardiac arrest. The over-triage rate using MPDS was 44%, which decreased to 33% using LA-TDS. LA-TDS was associated with significant improvements in specificity, positive predictive value and accuracy of initial resource assignment, and is projected to have saved over 23,000 EMS resource dispatches over the 9-month study period. Conclusion: The new Los Angeles Tiered Dispatch System significantly improved the efficiency of initial 9-1-1 resource assignments by decreasing both over-triage and critical under-triage, thus sending more appropriate resources to each 9-1-1 call.

Prime the Line! A Case Report of Air Embolism from a Peripheral IV Line in the Field.

Venous air embolisms are rare but a cause of potentially life-threatening events with associated cardiovascular, pulmonary and neurologic effects. We report the first prehospital case of a venous air embolism in a 31-year-old male who became hemodynamically unstable after a peripheral intravenous catheter with unprimed tubing was placed by paramedics in the prehospital setting and diagnosed in the emergency department. We highlight the clinical presentation, diagnosis and emergency management of venous air embolisms.

Advanced Practice Providers in the Field: Implementation of the Los Angeles Fire Department Advanced Provider Response Unit.

Background: To address the growing number of low-acuity patients in the 911-EMS system, the Los Angeles Fire Department (LAFD) launched a pilot program placing an Advanced Provider Response Unit (APRU) in the field so that a prehospital nurse practitioner (NP) could offer patients treatment/release on scene, alternative destination transport, and linkage with social services. Objective: To describe the initial 18-month experience implementing this new APRU. Methods: This is a retrospective, descriptive review of all APRU-attended patients from January 2016 to June 2017. The APRU was an ambulance staffed by an NP and a firefighter/paramedic, equipped with basic point-of-care testing capability, and linked to incidents by either being summoned by on-scene first responders or by monitoring EMS radio traffic. Descriptive statistics were used and outcome measures included counts of clients attended, treat/release rates, impact on total time in service for other LAFD resources, patient need for subsequent re-use of 911 and self-reported experience of care. Results: During its first 18 months in service, the APRU attended 812 patients, including 792 911-patient incidents. 400 of these 911-patients (50.5%) were treated and released on scene or medically cleared and transported to an alternative site for specialty care. This included 76 patients with primary psychiatric complaints who were medically-cleared and transported directly to a mental health urgent care center. An additional 18 high utilizers of 911 were attended by the APRU and connected with a social work organization, and 12 of 18 (66.7%) decreased their use of EMS in the 90-days following APRU evaluation and referral. Of the 400 911-patients that did not go to the emergency department (ED), 26 (6.5%) re-contacted 911 within 3 days: all were transported to the ED with normal vital signs and without prehospital intervention, and all were ultimately discharged home from the ED. As a result of APRU intervention, 458 other LAFD field resources were quickly placed back in service and made available for the next time-critical call. Conclusions: Advanced practice providers such as nurse practitioners can be incorporated into the prehospital setting to address a growing subset of 911-patients whose needs can be met outside of the ED.

Causes of Prehospital Misinterpretations of ST Elevation Myocardial Infarction.

OBJECTIVES: To determine the causes of software misinterpretation of ST elevation myocardial infarction (STEMI) compared to clinically identified STEMI to identify opportunities to improve prehospital STEMI identification. METHODS: We compared ECGs acquired from July 2011 through June 2012 using the LIFEPAK 15 on adult patients transported by the Los Angeles Fire Department. Cases included patients ≥18 years who received a prehospital ECG. Software interpretation of the ECG (STEMI or not) was compared with data in the regional EMS registry to classify the interpretation as true positive (TP), true negative (TN), false positive (FP), or false negative (FN). For cases where classification was not possible using registry data, 3 blinded cardiologists interpreted the ECG. Each discordance was subsequently reviewed to determine the likely cause of misclassification. The cardiologists independently reviewed a sample of these discordant ECGs and the causes of misclassification were updated in an iterative fashion. RESULTS: Of 44,611 cases, 50% were male (median age 65; inter-quartile range 52-80). Cases were classified as 482 (1.1%) TP, 711 (1.6%) FP, 43371 (97.2%) TN, and 47 (0.11%) FN. Of the 711 classified as FP, 126 (18%) were considered appropriate for, though did not undergo, emergent coronary angiography, because the ECG showed definite (52 cases) or borderline (65 cases) ischemic ST elevation, a STEMI equivalent (5 cases) or ST-elevation due to vasospasm (4 cases). The sensitivity was 92.8% [95% CI 90.6, 94.7%] and the specificity 98.7% [95% CI 98.6, 98.8%]. The leading causes of FP were ECG artifact (20%), early repolarization (16%), probable pericarditis/myocarditis (13%), indeterminate (12%), left ventricular hypertrophy (8%), and right bundle branch block (5%). There were 18 additional reasons for FP interpretation (<4% each). The leading causes of FN were borderline ST-segment elevations less than the algorithm threshold (40%) and tall T waves reducing the ST/T ratio below threshold (15%). There were 11 additional reasons for FN interpretation occurring ≤3 times each. CONCLUSION: The leading causes of FP automated interpretation of STEMI were ECG artifact and non-ischemic causes of ST-segment elevation. FN were rare and were related to ST-segment elevation or ST/T ratio that did not meet the software algorithm threshold.

Assessing the Risk of Prehospital Administration of Naloxone with Subsequent Refusal of Care.

BACKGROUND: EMS providers frequently encounter opioid-toxic patients who receive naloxone and then refuse further medical care. Older studies revealed this practice to be safe. In light of the evolving patterns of opioid abuse, this study attempted to determine the safety of this practice. METHODS: This is a retrospective review of all patient encounters by the Los Angeles Fire Department (LAFD) between July 1, 2011-December 31, 2013. All LAFD patient encounters are stored electronically. These electronic records were reviewed for subjects who received naloxone had a documented respiratory rate (RR) less than 12, and subsequently refused transport. Data abstracted included name, social security number (SSN), date of birth (DOB), date of EMS encounter, age, and treatment rendered. The names, SSN, and DOB, as available, were supplied to the coroner's office. The Coroner's records were reviewed to determine if a patient with the same or similar name (e.g., Jon vs. Jonathan) had died within 24 hours, 30 days, or 6 months of the initial EMS encounter. The abstractor was blinded to the study hypothesis. RESULTS: 205 subjects were identified; the median (IQR) age was 41 (29-53) years. 27 (13%) were female. One subject (0.49%) died within 24 hours of the initial EMS encounter. The cause of death (COD) was coronary artery disease and heroin use. Two additional subjects (1. %) died within 30 days. One of these subjects died 6 days later; the COD is unknown. The other subject died 20 days after the EMS encounter; the COD was cardiovascular disease and liver cirrhosis. No additional subjects were identified at the 6 month follow up. A third subject died of a heroin overdose 16 months after the initial EMS encounter, but was beyond the pre-defined follow up period. CONCLUSIONS: The practice of receiving pre-hospital naloxone by paramedics and subsequently refusing care is associated with an extremely low short- and intermediate-term mortality. Despite an evolving pattern of opioid abuse, the results of this study are consistent with previously reported studies.

Interfacility Transports Utilizing the 9-1-1 Emergency Medical Services System.

BACKGROUND: With the increasing development of regional specialty centers, emergency physicians are often confronted with patients needing definitive care unavailable at their hospital. Interfacility transports (IFTs) may be a useful option to ensure timely, definitive patient care. However, since traditional IFT can be a challenging and time-consuming process, some EMS agencies that have previously limited their service to 9-1-1 emergency responses are now performing emergency IFTs. OBJECTIVE: We sought to determine the frequency and nature of transfers provided by a local fire-based 9-1-1 EMS agency that recently began to provide limited IFT for time-critical emergencies. METHODS: A retrospective review of paramedic reports for all IFTs between April 2007 and March 2014 in the City of Los Angeles, California. All IFTs initiated by 9-1-1 call from an emergency department (ED) and performed by Los Angeles Fire Department paramedics were included. Reason for transfer, patient demographics, and key time metrics were captured. RESULTS: There were 919 IFTs during the study period, out of approximately 1,160,000 total ambulance transports (0.1%). The most frequent reason for IFT request was for transport of patients with ST segment elevation MI (STEMI) to a STEMI receiving center, followed by major trauma to a trauma center, and intracranial hemorrhage to a center with neurosurgical capability. Less common reasons included vascular emergencies, acute stroke, obstetric emergencies, and transfers to pediatric critical care facilities. Median transport time was 8 minutes (IQR 6-13 minutes) and median total time for IFT was 51 minutes (IQR 39-69 minutes). All IFTs involved a potentially life-threatening condition requiring a higher level of care than was available at the referring hospital. CONCLUSIONS: Emergent ED-to-ED interfacility transport can provide access to time critical definitive care. EMS agencies that have limited the scope of their response to community 9-1-1 emergencies should have policies in place to assure timely response for emergent IFT requests.

A Novel Algorithm for Improving the Prehospital Diagnostic Accuracy of ST-Segment Elevation Myocardial Infarction.

INTRODUCTION: Early detection of ST-segment elevation myocardial infarction (STEMI) on the prehospital electrocardiogram (ECG) improves patient outcomes. Current software algorithms optimize sensitivity but have a high false-positive rate. The authors propose an algorithm to improve the specificity of STEMI diagnosis in the prehospital setting. METHODS: A dataset of prehospital ECGs with verified outcomes was used to validate an algorithm to identify true and false-positive software interpretations of STEMI. Four criteria implicated in prior research to differentiate STEMI true positives were applied: heart rate <130, QRS <100, verification of ST-segment elevation, and absence of artifact. The test characteristics were calculated and regression analysis was used to examine the association between the number of criteria included and test characteristics. RESULTS: There were 44,611 cases available. Of these, 1,193 were identified as STEMI by the software interpretation. Applying all four criteria had the highest positive likelihood ratio of 353 (95% CI, 201-595) and specificity of 99.96% (95% CI, 99.93-99.98), but the lowest sensitivity (14%; 95% CI, 11-17) and worst negative likelihood ratio (0.86; 95% CI, 0.84-0.89). There was a strong correlation between increased positive likelihood ratio (r2 = 0.90) and specificity (r2 = 0.85) with increasing number of criteria. CONCLUSIONS: Prehospital ECGs with a high probability of true STEMI can be accurately identified using these four criteria: heart rate <130, QRS <100, verification of ST-segment elevation, and absence of artifact. Applying these criteria to prehospital ECGs with software interpretations of STEMI could decrease false-positive field activations, while also reducing the need to rely on transmission for physician over-read. This can have significant clinical and quality implications for Emergency Medical Services (EMS) systems.

Does Housing Status Matter in Emergency Medical Services Administration of Naloxone? A Prehospital Cross-sectional Study.

Introduction: Persons experiencing homelessness (PEH) use emergency medical services (EMS) at disproportionately high rates relative to housed individuals due to several factors including disparate access to healthcare. Limited access to care is compounded by higher rates of substance use in PEH. Despite growing attention to the opioid epidemic and housing crisis, differences in EMS naloxone administration by housing status has not been systematically examined. Our objective in this study was to describe EMS administration of naloxone by housing status in the City of Los Angeles. Methods: This was a 12-month retrospective, cross-sectional analysis of electronic patient care reports (ePCRs) for all 9-1-1 EMS incidents attended by the Los Angeles Fire Department (LAFD), the sole EMS provider agency for the City of Los Angeles during the study period, January-December 2018. During this time, the City had a population of 3,949,776 with an estimated 31,825 (0.8%) PEH. We included in the study individuals to whom LAFD personnel had administered naloxone. Housing status is a mandatory field on ePCRs. The primary study outcome was the incidence of EMS naloxone administration by housing status. We used descriptive statistics and logistic regression models to examine patterns by key covariates. Results: There were 345,190 EMS incidents during the study period. Naloxone was administered during 2,428 incidents. Of those incidents 608 (25%) involved PEH, and 1,820 (75%) involved housed individuals. Naloxone administration occurred at a rate of 19 per 1,000 PEH, roughly 44 times the rate of housed individuals. A logistic regression model showed that PEH remained 2.38 times more likely to receive naloxone than their housed counterparts, after adjusting for gender, age, and respiratory depression (odds ratio 2.38, 95% confidence interval 2.15-2.64). The most common provider impressions recorded by the EMS responders who administered naloxone were the same for both groups: overdose; altered level of consciousness; and cardiac arrest. Persons experiencing homelessness who received naloxone were more likely to be male (82% vs 67%) and younger (41.4 vs 46.2 years) than housed individuals. Conclusion: In the City of Los Angeles, PEH are more likely to receive EMS-administered naloxone than their housed peers even after adjusting for other factors. Future research is needed to understand outcomes and improve care pathways for patients confronting homelessness and opioid use.

Implementation of a regional extracorporeal membrane oxygenation program for refractory ventricular fibrillation out-of-hospital cardiac arrest.

BACKGROUND: eCPR, the modality of extracorporeal membrane oxygenation (ECMO) applied in the setting of cardiac arrest, has emerged as a novel therapy which may improve outcomes in select patients with out-of-hospital cardiac arrest (OHCA). To date, implementation has been mainly limited to single academic centres. Our objective is to describe the feasibility and challenges with implementation of a regional protocol for eCPR. METHODS: The Los Angeles County Emergency Medical Services (EMS) Agency implemented a regional eCPR protocol in July 2020, which included coordination across multiple EMS provider agencies and hospitals to route patients with refractory ventricular fibrillation (rVF) OHCA to eCPR-capable centres (ECCs). Data were entered on consecutive patients with rVF with suspected cardiac aetiology into a centralized database including time intervals, field and in-hospital care, survival and neurologic outcome. RESULTS: From July 27, 2020 through July 31, 2022, 35 patients (median age 57 years, 6 (17%) female) were routed to ECCs, of whom 11 (31%) received eCPR and 3 (27%) treated with eCPR survived, all of whom had a full neurologic recovery. Challenges encountered during implementation included cost to EMS provider agencies for training, implementation, and purchase of automatic chest compression devices, maintenance of system awareness, hospital administrative support for staffing and equipment for the ECMO program, and interdepartmental coordination at ECCs. CONCLUSION: We describe the successful implementation of a regional eCPR program with ongoing patient enrolment and data collection. These preliminary findings can serve as a model for other EMS systems who seek to implement regional eCPR programs.

Cognitive load during training for out-of-department emergency responses.

Background: Emergency medicine (EM) physicians sometimes respond to critical events outside the emergency department. To prepare for these complex cases-typically called "rapid responses" (RRs)-EM residents receive simulation-based training involving four practice tasks and three exam tasks during a 1-day session. Cognitive load (CL) theory describes how humans function with limited working memories to perform complex tasks. RRs are expected to generate high levels of CL, but the profile of CL across providers and RR cases is not well understood. In this study, we analyzed resident's CL during RR training. We hypothesized variations in CL across individual and case and that exam cases would cause higher CLs than practice cases. Methods: Residents anonymously self-reported CL levels after each case using the Paas scale, a single-item, 9-point scale from "very, very low CL" to "very, very high CL." To examine case-based differences in CL, data were rescaled by individual residents. "High CL" was defined as a score of 9/9. Results: Among 18 residents participating, CLs ranged from 4 to 9, with median of 7 and interquartile range of 7-8. While many cases showed bell curve-like distributions of CLs, one case-a bleeding tracheostomy-showed a rightward skew reflecting higher levels of CL. No significant difference was found in CL between practice and exam cases. There were 20 reports (16.5%) of "high" CL with variation across residents (0/7 [0%] to 5/6 [83.3%] cases) and across cases (1/18 [5.6%) to 8/18 [44.4%]). Conclusions: The CL that EM residents experienced did show considerable interpersonal and intercase variation, but there was no significant difference between practice and exam cases. These results highlight several questions about how to optimally design future training, including how best to balance low and high CL training cases and which cases may require further training.

Spatiotemporal analysis of out-of-hospital cardiac arrest in the City of Los Angeles, 2011-2019.

OBJECTIVE: The goal of this analysis is to spatiotemporally identify and categorize areas in a large urban city according to Out-of-Hospital Cardiac Arrest (OHCA) rates and No Bystander CPR (NBCPR) risk levels. STUDY AREA AND PARTICIPANTS: The study comprised all cardiac arrests within the administrative geographic boundary of the City of Los Angeles. The final sample included 15,904 cases that were geolocated within 985 census tracts. MAIN OUTCOMES AND MEASURES: The primary outcome was stratification of census tracts into risk levels of OHCA and NBCPR by observed spatiotemporal patterns. RESULTS: Of 985 census tracts in the analytical sample, 182 census tracts (18.5%) were identified as having higher risk of OHCA and NBCPR. This assessment resulted in 129 census tracts in Tier 3 (moderate risk), 36 in Tier 2 (moderate-high risk), and 17 in Tier 1 (highest risk). Census tracts in Tiers 2 and 3 had higher amounts incident OHCA, while those in tier 1 had more OHCA events with NBCPR. These areas were largely contiguous and located in the Central and South areas of Los Angeles. CONCLUSIONS: Using a novel three-tiered neighborhood risk classification tool, specific neighborhoods have been identified in the second largest city in the U.S. with consistently high or accelerating rates of OHCA and low bystander CPR. Further study of bystander response and community-based public health campaigns are needed in these communities.

Comparison of Emergency Medical Dispatch Systems for Performance of Telecommunicator-Assisted Cardiopulmonary Resuscitation Among 9-1-1 Callers With Limited English Proficiency.

Importance: Increasing bystander cardiopulmonary resuscitation (CPR) among racial/ethnic minority groups and culturally underserved populations is a key strategy in improving health care disparities in out-of-hospital cardiac arrest. Objective: To ascertain whether implementation of the Los Angeles Tiered Dispatch System (LA-TDS) was associated with improved performance of telecommunicator-assisted CPR (T-CPR) among 9-1-1 callers with limited English proficiency in the City of Los Angeles. Design, Setting, and Participants: This cohort study compared emergency medical services-treated, nontraumatic out-of-hospital cardiac arrest calls using the Medical Priority Dispatch System (MPDS) from January 1 to March 31, 2014, with calls using LA-TDS from January 1 to March 31, 2015. Trained data abstractors evaluated all 9-1-1 audio recordings for the initiation of T-CPR and the elapsed time to predefined events. Data were analyzed between January and December 2017. Main Outcomes and Measures: The primary outcome was the prevalence of T-CPR among 9-1-1 callers with limited English proficiency for field-confirmed nontraumatic cardiac arrests. Additional outcomes included T-CPR among callers with English proficiency and the elapsed time until key events in the call. Results: Of the 1027 emergency medical services calls during the study periods, 597 met the inclusion criteria. A total of 289 calls (48%) were made using MPDS (263 callers with English proficiency, and 26 callers with limited English proficiency), and 308 calls (52%) were made using LA-TDS (273 callers with English proficiency, and 35 callers with limited English proficiency). No differences between MPDS and LA-TDS cohorts were found in age, sex, known comorbidities, arrest location (private vs public), or witnessed status. The prevalence of T-CPR among callers with limited English proficiency was significantly greater using LA-TDS (69%) vs MPDS (28%) (odds ratio [OR], 5.66; 95% CI, 1.79-17.85; P = .003). For callers with English proficiency, the prevalence of T-CPR improved from 55% using MPDS to 67% using LA-TDS (OR, 1.66; 95% CI, 1.15-2.41; P = .007). With LA-TDS, callers with limited English proficiency had a significant decrease in time to recognition of cardiac arrest (OR, 0.59; 95% CI, 0.41-0.84; P = .005) and dispatch of resources (OR, 0.71; 95% CI, 0.54-0.94; P = .02). Conclusions and Relevance: The LA-TDS compared with MPDS was associated with increased performance of T-CPR for out-of-hospital cardiac arrests involving 9-1-1 callers with limited English proficiency. Further studies are needed in communities with a predominance of people with limited English proficiency to characterize bystander response, promote activation of the chain of survival, and clarify the precise elements of LA-TDS that can improve T-CPR performance.

Use of Naloxone in 9-1-1 Patients without Respiratory Depression in Los Angeles County, California (USA).

INTRODUCTION: Along with an increase in opioid deaths, there has been a desire to increase the accessibility of naloxone. However, in the absence of respiratory depression, naloxone is unlikely to be beneficial and may be deleterious if it precipitates withdrawal in individuals with central nervous system (CNS) depression due to non-opioid etiologies. OBJECTIVE: The aim of this study was to evaluate how effective prehospital providers were in administering naloxone. METHODS: This is a retrospective study of naloxone administration in two large urban Emergency Medical Service (EMS) systems. The proportion of patients who had a respiratory rate of at least 12 breaths per minute at the time of naloxone administration by prehospital providers was determined. RESULTS: During the two-year study period, 2,580 patients who received naloxone by prehospital providers were identified. The median (interquartile range) respiratory rate prior to naloxone administration was 12 (6-16) breaths per minute. Using an a priori respiratory rate of under 12 breaths per minute to define respiratory depression, only 1,232 (47.8%; 95% CI, 50.3%-54.2%) subjects who received naloxone by prehospital providers had respiratory depression. CONCLUSION: This study showed that EMS providers in Los Angeles County, California (USA) frequently administered naloxone to individuals without respiratory depression.

Implementation of the Los Angeles Tiered Dispatch System is associated with an increase in telecommunicator-assisted CPR.

BACKGROUND: In 2015, the Los Angeles Fire Department (LAFD) replaced the Medical Priority Dispatch System® (MPDS) with a new, homegrown Los Angeles Tiered Dispatch System (LA-TDS). The objective of this study was to assess the impact of this new dispatch system on telecommunicator-assisted CPR (T-CPR). METHODS: This was an interrupted time series study of out-of-hospital cardiac arrest (OHCA) cases where resuscitation was attempted with LAFD 9-1-1 telecommunicators using either MPDS® (January 1, 2014 to March 31, 2014) or LA-TDS (January 1, 2015 to March 31, 2015). Trained non-LAFD abstractors listened to all 9-1-1 calls and recorded if T-CPR was initiated, and the elapsed time from the start of the call until key events. The primary outcome was prevalence of T-CPR. RESULTS: Of 1027 calls during the study period, 597 9-1-1 calls met study inclusion/exclusion criteria (including 289 in MPDS cohort, 308 in LA-TDS cohort). The prevalence of T-CPR was significantly greater using LA-TDS (57%) vs. MPDS (43%) (OR 1.86, 95% CI 1.3-2.6). The LA-TDS cohort demonstrated a significant decrease (p < 0.001) in time to recognition of cardiac arrest, time to dispatch, and time to first T-CPR chest compression while there was no significant difference in the elapsed time to first description of agonal breathing. For cases where the telecommunicator had the opportunity to assess consciousness and breathing, there was a significant improvement in cardiac arrest recognition in < 1 min, prevalence of T-CPR (p < 0.001), and T-CPR started in <2 min (p < 0.001). CONCLUSION: Implementation of the new Los Angeles Tiered Dispatch System was associated with decreased time to recognition of cardiac arrest and an increased rate of T-CPR compared to the previously used Medical Priority Dispatch System®.